DESCRIPTION: Consumption of nitrite-preserved hot dogs by pregnant mothers has been associated with childhood brain cancer and leukemia. Exposure to N-nitroso compounds (NOC) may help cause gastric, esophageal and nasopharyngeal cancer. Hence we plan to identify apparent N-nitroso compounds (ANOC) that were detected but mostly not identified in nitrite-preserved foods and in human gastric juice. This will indicate if the ANOC are carcinogenic NOC. Our Specific Aims are: 1. We will determine ANOC in hot dogs and fried bacon, and in dried fish, fish sauce and soy sauce obtained from China. The determination will use sulfamic acid to destroy nitrite, NO liberation by HBr/HCl/HAc/refluxing EtAc and analysis of NO by thermal energy analysis (chemiluminescence). ANOC precursors in the foods will be separated and identified by standard chemical techniques. The derived ANOC will then be identified. 2. ANOC and their precursors in fasting gastric juice will be identified as in Aim 1 using large pooled samples of gastric juice and samples of normal acidic pH and of neutral pH, with attention to stable and labile ANOC fractions. 3. NOC will be produced by nitrosating the same foods and gastric juices, and analyzed for alkylnitrosoureas by HPLC monitored by on-line photolysis of NOC to give NO, which is determined by thermal energy analysis. 4. Since creatinine and 2 oximes derived from it by nitrosation are the most likely food constituents to yield nitrosoureas, these 3 compounds will be nitrosated and the kinetics of their conversion to methylurea and methylnitrosourea will be established, using the same method as in Aim 3 to determine MNU. The high temperatures formation of compounds from creatinine that could generate MNU will also be studied.